case $<variable> in <option1>) <statement>
;; <option2>) <statement> ;; esac
case $ch in +) res=`expr $a + $b` echo "Sum is: $res" ;; -) res=`expr $a - $b` echo "Remainder is: $res" ;; *) res=`expr $a \* $b` echo "Product is: $res" ;; /) res=`expr $a / $b` echo "Quotient is: $res" ;; esac